ABC of Safety in the Biological Sciences
Fumes or gases can be harmless or harmful. Many, but not all, may give warning of their presence by irritating the skin or mucous membranes, or by their smell.88 Some are odourless, even though they may be toxic and present in dangerous concentrations. Toxicity may be caused by skin contact, absorption through open cuts directly into the bloodstream or by inhalation. Any substance that gives off fumes should be used in a fume hood, even if not considered dangerous.89
Some of the more dangerous fumes or gases which may be encountered in the histopathology laboratory are ammonia, aromatic hydrocarbons (benzene, xylene),bromine, carbon dioxide, carbon monoxide, chloroform, formaldehyde, hydrochloric acid fumes, hydrogen sulphide, nitric acid, nitrous fumes, osmium tetroxide and sulphur dioxide.
Fumes or gases can also be inflammable, especially those produced by the aromatic hydrocarbons of which ether is a good example. Formaldehyde gas can be explosive when confined. It is advisable to have a respirator, that contains a suitable absorbent, available for accidents involving fumes or gases. Persons affected by gas or fumes should be removed immediately to fresh air (if the agent is still present a respirator must be worn by the person effecting the recovery of the affected). Breathing should be checked and if necessary artificial respiration or oxygen administered.
Some poisonous gases lead to convulsions which, after subsiding, may be brought on again by alcohol, noise or excitement. Medical advice should always be obtained after any case involving poisoning by gas.